Wireless access networks have become a key element of a variety of telecommunications network environments. As to enterprise network environments, they provide convenient wireless access to network resources for employers or customers carrying laptops and/or mobile handheld devices. In addition, wireless access points operable with diverse communication devices, such as laptops, mobile phones, etc., are broadly used in public environment such as e.g., hotels, train stations, airports, restaurants, schools, universities and homes, and are mostly used to offer high-speed interne access.
The telecommunication industries and operators are currently investigating the possibility to further increase the coverage area offered by cellular communications network systems to home or small areas. Example of cellular communication network system are: the Universal Mobile Telecommunication Systems (UMTS) network, also known as third generation (3G) cellular network system or wideband code division multiplexing access (WCDMA); the Global System for Mobile telecommunications (GSM) network; the General Packet Radio Service (GPRS) network that utilizes the infrastructure of a GSM system; Two further examples of cellular access networks are EDGE and EGPRS which are further enhancements to GSM and GPRS. EDGE refers to enhanced Data rates for GSM Evolution, and EGPRS refers to EDGE for GPRS.
According to such investigation, a limited number of users (e.g. a user equipment (UE)) may be provided with e.g. WCDMA or 3G coverage using a small radio base stations (RBS) also called a “femto RBS” that would be connected to a radio network controller (RNC) of the 3G network using some kind of interne protocol (IP) based transmission. The coverage area so provided is called a “femto cell” to indicate that the coverage area is relatively small compared with an area of a macro cell. Other terminology for a femto RBS includes a “Home RBS” and/or a “pico RBS” and/or a “home 3G access point (H3GAP)” and/or a “micro RBS” and/or a “home access point (HAP)” and/or a “home Node B (HNB)”.
One alternative for the IP based transmission is to use fixed broadband access (like xDSL, Cable, etc.) to connect the femto RBS to the RNC. Another alternative would be to use mobile broadband access e.g. HSDPA and enhanced uplink or some WiMAX technologies.
FIG. 1 illustrates an example of a WCDMA network 1 including femto RBSs 40 working as H3GAP. As shown, the network 1 comprises a core network (CN) 10 connected to one or more RNCs 20 that control all radio base stations connected to it, i.e. macro RBS 30 and femto RBSs 40. The macro RBS 30 serves a macro cell 31 whereas a femto RBSs 40 serves a femto cell 41. As illustrated, each femto RBS 40 serves its dedicated femto cell 41.
As well known in the art, a RBS is typically situated at an interior (e.g. center) of the respective cell which the RBS serves, but for the sake of clarity, the macro RBS 30 and the femto RBSs 40 of FIG. 1 are shown instead as being associated by double headed arrows to their respective cells. At least some of the femto cells 41 are geographically overlayed or overlapped by the macro cell 31.
A user equipment (UE) 50 communicates with one or more cells or one or more RBSs over a radio interface. A UE can be a mobile phone (or “cellular phone”), a laptop with mobile termination and thus can be e.g. portable, pocket, handheld, computer-included, or car-mounted mobile device which can communicate voice and/or data with a radio access network. The UE 50 my further communicate with the radio access network via a femto RBS 40 through an IP based transmission network 60 which, as described earlier, can be either broadband fixed IP based transmission (e.g. xDSL) or broadband mobile IP based transmission (e.g. WiMax).
In the WCDMA network depicted in FIG. 1, the transport network capacity (or bandwidth) between the macro RBS 30 and the RNC 20 is usually known in advance. The information on the network capacity may be used by an operator for e.g. congestion and admission control within the RNC 20. However, the network capacity (or bandwidth) between the femto RBS 40 and for example a network node 61 being either part of the IP network 60 or connected to the IP based network 60, is more unpredictable especially when thousands of femto RBSs may be deployed in the network making it more difficult to determine distances between femto RBSs and network nodes of the IP based network 60. Such IP network node may e.g. be a digital subscriber line access multiplexer (DSLAM) linking the femto RBS to the RNC. Thus, without knowledge of this network capacity, congestion and admission/access control within a femto cell served by a femto RBS is more difficult to achieve leading to unnecessary waste of resources and capacity in the femto cell.